Osteogenic effect of heterogenic rat MSCs: a preliminary study

Objective To observe osteogenic effect of heterogenic rat mesenchymal stem cells(MSCs) in vivo.Methods Two kinds of tissue engineering bones were formed by demineralized bone matrix(DBM) and MSCs(A group) and undergoing osteogenic MSCs(B group) respectively from BN rats and transplanted into F344 rats.DBM without cells was the control group(C group).The osteogenic effect of grafts was observed by X-ray,HE staining and serum alkaline phosphatase(ALP).Results X-ray showed that cloudy bone image with obscure boundary appeared in group A and B at 12 week,but not in group C.The images became clearer at 18 week than at 12 week in group A and B.At the same time,cloudy bone image was observed in group C.HE staining revealed inflammatory cell infiltration around DBM at 6 week in all groups,but no newly formed bone trabeculae.At 12 week,the number of inflammatory cells was reduced,and more newly formed bone trabeculaes were observed in group A and B.At 18 week,bone trabeculae of group A and B tended to mature compared with group C,and inflammatory cells disappeared.At 6 week,the level of serum alkaline phosphatase was the lowest.The level of serum alkaline phosphatase at 12 week increased compared with that at 6 week.The level of group B was higher than that of group A,and they were both much higher than that of group C.The situation at 18 weekwas similar to that at 12 week.Conclusion Tissue-engineered bone constructed with heterogenic MSCs either undergoing osteogenic induction or not exhibited the capability of ectopic osteogenesis,suggesting that heterogenic MSCs may act as seed cells for bone tissue engineering and be used to contruct heterogenic tissue-engineered bone.